Study Of Blade Coating Large-area And Flexible Organic Solar Cells With High Performance

This work deeply studies organic solar cells with different active system based on industrialized doctor-blading technology.Firstly,nonfullerene system of PTB7-Th:ITIC with doctor blading technique by incorporating various ratios of DIO.A very high PCE of 9.54%is obtained.Furthermore,nonfullerene solar cells is fabricated with a large-area(2.03 cm~2)flexible ITO-free structure and a remarkable PCE of 7.60%is achieved,which is much higher than the spin-coating one under same conditions.The results show that adding appropriate DIO can effectively optimize morphology,crystallinity,charge recombination and transport of the nonfullerene active layers.Moreover,all-polymer system of PTB7-Th:PNDI-T10 is combined with doctor-blading technique.It is found that adding small amount of DIO can prolong the drying time of active layer from 120 to 1000 s at room temperature,and eventually a high PCE of 8.61%is obtained.Furthermore,this printing technique is transferred to large-area flexible ITO-free structure and a remarkable PCE of 6.65%is also achieved.We explain above experimental results in detail.Lastly,self-assembly interface layer is mixed with fullerene system and fabricate solar cells by using doctor blading technique.It is encouraging that the PCE of 6.56%is obtained in one-step doctor blading devices under 25°C substrate temperature,which is comparable with two-step devices under the same substrate temperature.This is mainly because low substrate temperature leads to completely self-assembly interface layer to improve charge separation and transport.On the contrary,the optimal substrate temperature in two-step devices is 60°C,which is related to the good morphology and appropriate crystallinity.